Deslimer and classifier



y 6, 1929. J. R. WRIGHT 1.720.810

DESLIMER AND CLASSIFIER Filed fi 1927 2 Sheets-Sheet 1 July 16, 1929. J.R. WRIGHT DESLIHER AND CLASSIFIER File Aug- 192'! 2 snaps-sheet 2dirk/lava fl/PzW/r Patented July 16, 1929.

PATENT OFFICE.

JAMES RAYMOND WRIGHT, OF DENVER, COLORADO.

DESLIMER AND CLASSIFIEB.

Application filed August 5,

* removing the fines and slimes from the pulp feed to the gravityconcentrating apparatug of the mill so that the treatment of the coarsermaterial by gravity will not be in terfered with and so that the slimescan be collected for chemical, flotation or other treatment. Theinvention is also designed for use on the tailings from the gravityconcentrating apparatus so that the coarser material which has beentreated can be discharged as valueless and the fines, which the gravitymachines could not treat properly, can be returned for proper treatmentwith the slimes from the mill feed.

The principal object of the invention is to provide a continuouslyoperating classifier or deslimer which will not interfere with thecontinuous feedflow required for proper concentration, which will behighly e-fiicient in operation; which will require but a minimum ofwater; and which will not become choked or clogged.

Another object of the invention is to provide a machine which can beused to prevent the slimes from being'lost with the gravity tailings andwhich will at the same time dewater and save a largetpercentage of thewater usually lost with thetailings of a mill. This last object, ofcourse, becomes valuable in proportion to the value of the water at themill site.

A further object is to provide a machine through which the coarsermaterial will pass in a continuous flow and in which the tines will becollected and stored to be discharged at intervals or continuously asdesired.

Other objects and advantages reside in the detail ccmstruction of theinvention, which 1927. Serial No. 210,786.

ciency. These will become more apparent from the following description.

In the following detailed description of the invention, reference is hadto the accompanying drawings which form a part hereof. Like numeralsrefer to like parts in all views of the drawings and. throughout thedescription.

In the drawings:

Fig. 1 is a longitudinal vertical section through one form of myimproved machine. This view is taken on the line 11, Fig. 2.

Fig. 2 is an elevation of the discharge end of the machine of Fig. 1.

Fig. 3 is a fragmentary plan view of a typical one of the feed boxesemployed on the machine.

Fig. 4 is a side elevation partly broken away of an alternate form ofthe machine to be later described.

Fig. 5 is a cross section,-taken on the line 55, Fig. 4,throughthealternateform of the machine.

Fig. 6 is'a detail crosssection taken on the line 6-6, Fig.1,illustrating in diagram the classifying action of the machine.

The invention comprises all of the features, parts and detailsof-construction and combinations thereof hereinafter described which arenecessary or useful in accomplishing the object of the invention.

In all forms of the invention a relatively long v.V-shaped tanklO isemployed, in which a suitable roll supporting frame 11 is carried,extending throughout the. length of the tank, for the support of arelatively wide endless belt 16. A relatively short idler belt 15 iscarried between each pair of idler belt rollers 13. The idler belts,being relatively short, can be kept sufiiciently tight so that any sagtherein will not be apreoiable. These idlernbelts maintain. an almostcontinuous plane surface for the support of the belt 16 andprevent anysag lnits upper reach or working surface. .The return reach of the belt'16 is supported on return rollers 14, from whence it'turns overa tailroller l2 to its upper reach on the idler belts.

An angularly placed pressure belt 17, carried on ressure rollers 18, isprovided, against wiiich, thenpper reach of the belt 16 bears .asitpasses titan-.11 ward an 1e out of the solution in 1 the .tanli .10 anover an elevating roller. v19. to: a drivingroller beyond the extremityof the tank. The lower reach of the belt 16 returns from the drivingroller 20 over the end of the tank on a similar elevating roller 21 to ahead roller 22 which aligns it with the return rollers 14.

Pulp is fed to the machine by one or more launders 23 in either a dry orfluid suspended condition. The pulp is received in feed boxes 24, onebox being placed below each of the launder-s 23.

The feed boxes 24 are relatively long, narrow boxes provided withperforated o1 screened bottoms 25. They are arranged along the medialline of the belt 16 with their greatest length parallel thereto andtheir bottoms parallel to and spaced above the belt. Baffie boards 26extend entirely across the tank 10 at each end of each of the feed boxes24, in fact they may form, if desired, the ends of the boxes asillustrated. These baffle boards 20 may extend entirely across the belt16 and are suspended just above the beltsurface. The number of feedboxes is optional depending upon the length of the tank 10 andthecapacity desired.

'lVhen employing the machine to prepare the pulp for concentratingapparatus, the pulp is fed to the feed boxes directly from the crushers,preferably mixed with water.

It enters the solution in a quiescent zone enclosed in the feed box andslowly filters through the perforated bottom 25, causing a mild currentto flow from the center line of the belt 16 outwardly toward both edgesthereof, as shown in Fig. 6. This current is forced to flow in a lateraldirection by being confined between the laterally extending baflleboards 26. The coarse, heavy particles fall directly to the belt andaccumulate along its mid-portion. The fines and slimes stay insuspension longer and are carried by the current over the edges of thebelt into the tank 10.

There will be a classification of the pulp upon the belt ranging fromthe coarsest material. along the center line to fine material at itsedges. The amount of fine material retained depends upon the amount ofwater admitted with the pulp, which of course, effects the speed of theclassifying current, and also on the speed at which the belt istraveling. 7

Should it be found that too large a percentage of fines remains on thebelt, the

, sible.

tance of conveyance.

that the first deposited pulp will be subjected to further classifyingcurrent under the subsequent boxes, should more than one box be used.The subsequent currents, however, are not of sufiicient strength tocause any loss in the coarser particles deposited. After passing fromunder the lastfeed box, the belt turns upwardly to emerge from thesolution. At this point, the pressure belt contacts with the upper beltsurface and prevents the surface tension from drawing the depositedmaterial back into the solution.

The majority of the pulp falls from the belt 16 as it passes around thedriving roll 20 into a receiving hopper 28. Any residual pulp may bewashed from the belt by means of a water spray 29, or may be brushedtherefrom by means of a suitable brush, as is common in vanner practice.The pulp is conveyed from the receiving hopper through a launder 27 tothe concentrating apparatus. The belt may be driven by any suitabledrive mechanism, such as a belt pulley 30 and drive belt 31. The finesand slimes settle to the V-shaped bottom of the tank,

and are conveyed along the bottom by means of a screw conveyor 32 to areceiving box 33. It is preferred to make the conveyor right and lefthand so that it will be double acting, as illustrated, so as to shortenthe dis- The fines soon pack and form a bottom or lining around theconveyor which prevents wear on the tank.

The slimes may be discharged at suitable intervals, or continuously,through a gate valve The screw conveyor 32 may be rotated in any desiredmanner, such as by a sprocket 35 and sprocket chain 36. The frame 11extends over the extremity of the tank 10 so as to support all of therollers both on the interior and exterior of the tank. It may beattached to the tank by means of suitable flanges, as shown at 3L.

In the alternate form of the invention, illustrated in Figs. 4 and 5, areceiving tank 38 is attached to the discharge end of the tank 10. Thereceiving tank is open to the tank 10, so as to receive solutiontherefrom and maintain a solution level equal to that in the tank 10.This receiving tank may be supported on an extension 10 of the frame 11and is so arranged that a drive roller 41 similar to the drive roller20, previously described, will cause the belt 16 to partially submergein the Water of the receiving tank 38. This submergence washes the pulpfrom the belt, allowing it to settle to the bottom of the receiving tank38.

The bottom of the receiving tank is inclined and contains a screwconveyor 39 which elevates the deposited pulp above the solution levelin the tank and allows the water to drain from the pulp back into thetank. This form of the invention is especially valuable where it isdesired to save water since the same water that is used in the tank 10is also used to wash the pulp from the belt at the discharge, no pumpbeing required. The main belt constantly adds water, to the receivingtank 38 so that there is a slight current into the tank 10 through theopening 37. This current carries back any slimes which may have beenaccidentally carried over by the belt.

This form has a special application in dewatering and desliming thetailings discharged from a gravity separation machine, such as aconcentrating table. These gravity machines operate efficiently on thecoarser particles so that the tailings from these machines carry barren,coarse gangue and metal bearing fines. By discharging the tailings intothe tank 10, these coarse, barren particles can be separated from thevalue carrying lines and slimes. The coarse tailings are carried up theinclined bottom of the receiving tank 38 by the screw 39 and dischargedinto the tailings dump. These tailings carry very little water sincethey are drained on this inclined bottom so that loss of water in thetailiugs is reduced to a. minimum. The slimes which have not receivedtheir proper treatment are then reconveyed to the mill system from thetank 10 and are treated by processes, such as flotation, etc., suitableto their fineness.

The feed boxes 24 may be supported from the battle boards 26, which canbe extended from side to side of the tank 10, if desired as illustratedin Figs. 2 and 6. The tank 10 may be supported on cross beams 42 fromwhich project angle braces 43 throughout the length of the tank.

\Vhile a specific form of the improvement has been described andillustrated herein, it is desired to be understood that the same may bevaried, within the scope of the appended claims, without departing fromthe spirit of the invention.

Having thus described the invention, what I claim and desire to secureby Letters Patent is 1. In a classifying device having a belt adapted toraise settled material from a liquid in a tank, means for preventing thesurface tension of said liquid from drawing said material from said beltas it emerges comprising a second belt adapted to lie against andcontact with the carrying surface of said first belt along the portionof the latter which is emerging from the liquid.

2. A device for separating the fines from ore pulp comprising: aV-shaped liquid containing tank; a belt adapted to move horizontally insaid tank below said liquid; means for causing said belt to rise abovesaid liquid a portion of its travel; a second belt adapted to lieagainst and contact with that portion of the first belt rising abovesaid liquid so as to prevent the surface tension of said liquid fromdrawing material from said belt as it emerges; means for removingmaterial from said first belt after it leaves said second belt; andmeans for placing material in said liquid along the center line of saidfirst belt.

A device for separating the fines from ore pulp comprising: a V-shapedliquid containing tank; a belt adapted to move horizontally in said tankbelow said liquid; means for causing said belt to rise above said liquida portion of its travel; a second belt adapted to lie against andcontact with that portion of the first belt rising above said liquid soas to prevent the surface tension of said liquid from drawing materialfrom said belt as it emerges; means for removing material from saidfirst belt after it leaves said second belt; and means for placingmaterial in said liquid along the center line of said first belt; saidsecond belt initially contacting with the material on said first beltbelow the surface of said liquid.

In testimony whereof, I affix my signature.

J. RAYMOND V RIGHT.

